virtio: support modern devices

fixes #17239 #17238

Change-Id: Ia5b6347110a60fab18852079b30dca6301010474
Reviewed-on: https://review.haiku-os.org/c/haiku/+/6995
Reviewed-by: Jérôme Duval <jerome.duval@gmail.com>

virtio: add driver for the virtio balloon device

* how-to for qemu: command line option: -balloon virtio
* in the monitor view
- to switch the vm size to 500MB: balloon 500
- to display balloon info: info balloon